New Zealand star Beauden Barrett has admitted it will be both "exciting" and "weird" to play against his former Hurricanes team-mate Brad Shields when the All Blacks face England at Twickenham on Saturday.

The 27-year-old Shields was born and raised in New Zealand but to English parents.

Having failed to gain selection for the All Blacks, the flanker was catapulted into the England set-up, winning the first of his three Test caps against South Africa in Johannesburg in June.

"It's very exciting," said Barrett when asked about playing against Shields.

"I don't know how I feel about it. It's going to be weird. Hopefully I don't see him out there too much because he's a big brute and he'll probably try to line me up."

Shields temporarily lodged at fly-half Barrett's home in Wellington before flying to England to join new club Wasps.

Barrett, after his superb four-try haul against Australia in August, returned to discover Shields had left him an unusual present -- his England training top.

"It's still there," Barrett added Thursday. "I didn't bring it over with me, but yeah, it was quite cheeky of him."

But the serious point illustrated by Shields' inclusion in England's back-row is that New Zealand boast a wealth of rugby talent not all of which can be accommodated by the world champion All Blacks.

For example, England co-captain Dylan Hartley was born and brought up in New Zealand before the hooker headed to his mother's homeland as a teenager.

Meanwhile former All Blacks head coach John Mitchell recently joined the England set-up as Australian boss Eddie Jones' new defence guru.

Warren Gatland is the long-serving Kiwi coach of Wales, with compatriot Joe Schmidt guiding Ireland to a Six Nations Grand Slam last season.

- 'Tug at his heart-strings' -

Steve Hansen, the New Zealand head coach, said Shields was in for an "emotional" time on Saturday.

"He's going to be facing a team he always wanted to play for but unfortunately for him we didn't pick him," he explained.

"Some of his great mates are in that team," added Hansen, who was himself in charge of Wales before returning home to join the All Blacks' staff, initially as an assistant to Graham Henry.

"He will find it emotional...he's a quality man, a good rugby player, and he will deal with it in his own way.

"But it will tug at his heart-strings. You wouldn't be human if it didn't."

As for his own experience of coaching Wales against New Zealand, Hansen said: "It wasn't that pleasant because we got thumped. It's emotional."

But he said the much-travelled Mitchell, sacked as All Blacks boss after their 2003 World Cup semi-final defeat by an Australia-coached Jones in a tournament eventually won by England, would find this weekend's match less of a strain.

"John has been away from New Zealand for a long time, so I don't know if he still harbours those emotions."

Hansen added there was no secret as to why New Zealanders were in demand as either players or coaches at wealthy leading European clubs and countries.

"I don't want to sound big-headed but I think it's because they want success," said the 59-year-old.

"A lot of the New Zealand ingredients bring success to clubs. The players have been successful, hence they pay good money for them or the coach is someone they think can impart successful knowledge to the players.

"Success breeds success -– and creates a lot of myths or a lot of truths. You get employed and you have to make sure it is truths not myths."